Making you come in Four lessons
by CloakSeeker
Summary: Disclaimer: I do not own the Divergent series. This is a one-shot, it's a requested smut. Tobias and Tris go to high-school, he is two years her senior, but she is a mathlete and helps him with his math exam. They end up playing student and teacher.
1. Chapter 1

**A/N: This is a request from my friend Nalurah and a few other people who are loyal readers. This smut-shot was planned for a long time, but I thought today is the best day to write and post it, since it's the birthday of my girl Nalurah. Happy Birthday, sweetie! You already got the Dauntless cake from me. Don't be mad, but I shared it with Four and Tris. Or rather Four smeared it all over... Nah, I'm not saying more. Enjoy!**

"How come you don't get it?" I ask him. "You had this two years ago" I say and he frowns.

"Not all of us are good at math, babe" Tobias says and comes over to hug me.

"Tobias, you need to study, otherwise you'll fail class" I scold him.

"It's just so fucking hard" he says with furrowed eyebrows, before his expression changes to a smug one. "You know what else is hard?" he asks with a mischievous grin, grabbing my hand and placing it over the bulge in his pants. "I am. For you, baby."

"Tobias" I say giggling. "Stop it" I try to be more serious but fail. "You need to study."

"Can you help me?" he asks half serious, but I know he has only one thing in mind right now.

"How can I help you? You are two years my senior" I say, although I'm a mathlete and he knows it. He raises an eyebrow and gives me a _are you kidding me_ look. "Alright, but you have to promise you'll behave."

"I promise to try" he says and kisses my cheek sweetly.

"That's good for me. For now anyways. Let's start."

We both sit next to each other at my desk and I show him some integral equations. I start out by showing him different kinds and explain them to him. After we survey them several times I write one down and ask him to identify it.

∫(x)= ∫_a^b K(x,t)φ(t)dt

"So, what is it?" I ask him. He looks at it like it's alien and frowns. "Come on, Tobias. I know you know it" I say encouragingly. "It's the most basic integral equation."

"Fredholm equation?" he asks unsure.

"Yes. That's correct. What does _φ_ stand for in the equation above?" I ask him and he looks at me like I just punched him in the face. "You know it."

"Tris, we've been studying for hours. Can't we take a break?" he asks with puppy dog eyes.

"Only after you answer my question" I say, looking at him as sternly as I can.

"What was the question again?" he asks smirking.

"What does _φ_ stand for in the equation above?"

"Here _φ_ is an unknown function, _f_ is a known function, and _K_ is another known function of two variables, often called the kernel function. Note that the limits of integration are constant; this is what characterizes a Fredholm equation" he answers like a pro.

"See? Told you that you know it" I say smiling.

"With a teacher like you any student knows the right answer, even a butthead like me" he says and leans in to kiss me, but I raise my hand between our lips. He frowns.

"You are not a butthead. You just like to pretend you are one so that you have an excuse to come over and make out" I say.

"Hey, you are my girlfriend" he says.

"That I am. And you know what?"

"What?"

"We are all alone here. Mom and dad went to some charity party. And Caleb is out on a date and won't be back for a long while" I say smirking.

"Oh" is all that he says. "Well, then. I've got an idea. Since you are already sort of my teacher, what about we play a little student and teacher?" he asks.

"You naughty little shit" I say and he laughs.

"Is that a yes?" he asks hopeful.

"Mr. Eaton, if you don't behave this instance I will have to punish you" I say, getting into character.

"Yes, ma'am" he answers.

"Now, let's see. I think a test is due today, don't you agree, Mr. Eaton?" I ask.

"Why yes, Ms. Prior. I sure hope I do well."

"I'll ask you questions and for each right answer that you give me, I'll take a piece of clothing off. If you answer wrong you'll have to get rid of one of yours. Understood?" I ask and he nods enthusiastically.

"Ms. Prior, I have a question before we start" he says and I nod for him to continue. "What happens when we're both naked?"

"Ah, that's part two of the test. I'll explain more when we get there" I say and he grins. "Ready?" He nods. "What is 2+2?" I ask and he laughs a little.

"Four, just like my nickname" he answers.

"Correct" I say and take off my tee shirt. "Next questions. What's 78-10?"

"Uhm, 12?" he answers deliberately wrong.

"Wrong. It's 68. You have to take something off" I say and he gets rid of his shirt as well.

"What's 3x3?"

"Nine" he answers and I take off my skirt.

"What's 12:2?"

"Seven."

"Wrong" I say and he takes his pants off. I'm down to bra and panties and he is still in his briefs and socks.

"What's 7+7?"

"Fourteen" he answers and I take my bra off revealing my breasts to him. Both my nipples stand erect from both the chilly air in my room and the arousal I feel right now. His eyes are glued on the exposed mounds and I feel blood rush into my cheeks.

"What's 9-8?" I continue.

"Two" he answers wrongly and takes off his socks.

"What's 1+1?"

"Two" he answers again and I stand up, but before I pull down my panties I ask my last question.

"What's 2-1?"

"Zero" he answers and stands up as well. He takes a step forward and places his hands on my hips pulling me closer to him. Our lips connect and we kiss each other passionately. However, he breaks the contact too soon and before I know what he's doing he gets down on his knees and pulls my panties off, leaving me bare in front of him.

"Mr. Eaton, you're last answer was wrong. You need to remove your briefs as punishment" I say, breathing heavily.

He does as instructed and removes his briefs freeing his impressive manhood, which stands tall in front of me, twitching in anticipation.

"What now, Ms. Prior?" he asks and I drag my eyes away from his delicious cock.

"Uhm…" I stutter and he laughs lightly.

"You are the teacher. You tell me what to do" he says, but helps me nevertheless to regain my voice. "You said once we're naked we'll proceed to the next stage of testing" he explains.

"Ah right. Now, for this stage I will ask you about a few theorems and if you are right I'll blow you and if you are wrong you will have to safe your grade by making me come just with your mouth and tongue" I say and blush a little.

"Alright, Ms. Prior. I will trust your teaching skills" he says with a smirk.

"Good. Pythagoras's theorem" I say and he smiles.

"The theorem states that the square of the hypotenuse is equal to the sum of the squares of the other two sides. The theorem can be written as an equation relating the lengths of the sides a, b and c" he answers. I nod my head.

I grab his hand and pull him to my bed were I motion him to sit down. He does as instructed while I kneel in front of him between his parted legs. I look up at him and smile. I envelope his length with my small hand and stroke him gently. He gasps audibly and I smile up at him. I stroke him a few more times before placing a soft kiss to his tip. He moves his left hand into my hair and holds my head close to him. I lick my lips to moisten them before opening my mouth as wide as I can and take him in. I watch him as I bob my head up and down his meaty cock and he throws his head back in pleasure. He is too large for me to suck his entire length and I make up for it with my hand. I release his cock and lick the outside from base to tip on the underside and then from tip to base on the other side. I lick and suck his balls and he moans loudly my name.

"Oh my God, Tris, I'm close" he pants heavily. I smirk and take him back in. I increase my pace every once in a while until I feel him stiffen and release his seed deep inside my throat. I swallow his load greedily and release him with a loud popping sound. "Fuck, babe, that was awesome" he says filling his lungs with much needed air. "Thanks."

"My pleasure" I say and crawl up on the bed.

"Oh, no. The pleasure was all mine" he says with a smug grin on his face.

"Ready for your next question, Mr. Eaton?" I ask.

"Whenever you are, teacher" he says and kisses my lips softly.

"Alright. What does the Poincare-Birkhoff theorem state?" I ask and he looks at me confused.

"I have no fucking idea" he says and I give him a look. "Honestly, babe. I don't know."

"Okay. Then I'll have to explain it to you." I lie down on my back in the middle of my bed and spread my legs. He smirks and settles between them. He lies on his stomach and his face is inches away from my moist womanhood. I'm so wet for him.

"Babe, I don't know how long I can take not fucking you any longer. I'm so hard for you" he says and I giggle. He looks at me confused.

"I sorry, honey. I was just thinking how wet I am for _you_ " I tell him and he smiles before kissing my entrance.

"I can tell. So, Ms. Prior, you wanted to teach me about this Point beer theorem" he says and I laugh out loud.

"Poincare-Birkhoff theorem" I correct.

"Same thing. So, start explaining, while I eat your delicious pussy" he says and my breath catches in my throat. He places his elbows on the bed to sustain his weight, while his arms snake around my thighs. He kisses the inside of my right thigh at first and then turns his head and kisses my left.

"In symplectic topology and" I stop abruptly when he licks my folds. "And dynamical systems, Poincare-Birkoff theorem, also known as Poincare-Birkoff fixed point theorem, states that" I stop again when he pushes his tongue inside my wet pussy. He retracts it only to capture my throbbing nubbin between his teeth and sucking on it. I throw my head back into the pillow, close my eyes and moan his name.

"I know you said mouth and tongue, but can I use a finger? Or two?" he asks and I nod without opening my eyes. While he's still licking my folds he inserts two fingers at once and starts pumping. "What else, babe? I'm still not clear on this theorem" he says and I open my eyes to look into his beautiful dark blue ones. He is hovering over me, while his fingers pump relentlessly into me, bringing me closer and closer to oblivion.

"Uhm, where was I?" I ask dazed?

"You said the theorem states but stopped. What does the theorem state, honey?" he asks with a wide grin on his face.

"The theorem states every area-preserving, orientation-preserving homeomorphism of an annulus that rotates the two boundaries in opposite directions has at least two" I stop again when I feel my release nearing rapidly. I grab the sheets into my fists, arch my back and yell out Tobias's name when I come hard on his hand. When I fall back onto the bed Tobias looks at me lovingly and places soft kisses on my lips. He withdraws his fingers from inside me and sucks them clean.

"Best pussy ever" he says and I laugh at him.

"I love you" I say and reach up to cup his face.

"I love you too" he says and leans down to capture my lips with his. We kiss for a long while until air becomes an issue. We part and look deep into each others eyes, when I remember I never finished my sentence.

"At least two fixed points" I say and he looks at me confused, so I repeat the entire sentence. "The theorem states every area-preserving, orientation-preserving homeomorphism of an annulus that rotates the two boundaries in opposite directions has at least two fixed points."

"Leave it to you to explain math to me during sex" he says laughing.

"Shut up. I'm still your teacher" I say.

"Alright. What's my next task?" he asks.

"Solve the integral equation I gave you to recognize" I say. He looks at me and furrows his eyebrows.

"What if I don't?" he asks.

"Then you won't receive any of the cake I baked" I say. At the mention of cake he looks at me both surprised and anxious.

"Your parents are gone, right?" he asks and I look at him confused.

"Yeah, I already told you that. Why?" I ask but he ignores my questions and asks one in return.

"And your brother is out on a date, right?" he asks and I nod. He smirks and kisses my lips before jumping up. "Wait here." He runs out of my room and returns a minute later with the cake.

"Tobias, what are you doing?" I ask amused and concerned. He is up to something. I know it.

"I'm going to teach you something. It's about time our roles change a bit" he says with a sexy smile.

"Alright, Mr. Eaton. You'll be the teacher from now on" I say and can hardly wait for him to start.

"First, Ms. Prior, lay back and relax" he instructs. I do as he says. "Now, tell me. Is this cake just for me or is it for your parents and brother as well?"

"Just for you, baby."

"Good" he says and grabs a handful of cake and smears it all over my body. The coolness of the icing makes my nipples stand erect, aching for his warm, wet mouth.

"How's this teaching?" I ask.

"Hang on. You'll understand in a minute" he says while running his cake filled hand over my belly and down to my womanhood. He crawls back up and hovers over me.

"Lick this clean" he says holding his hand up. I grab it and start licking the cake remnants of it. He moans loudly when I take his middle finger in my mouth and look through my lashes at him as seductively as I can. "Fuck, you're sexy when you do that" he says and I grin.

"So, what's this lesson you want to teach me?" I ask him when I finally let go of his hand.

"Right. Lesson number one. The licking of the breasts, followed by lesson number two: how to properly suck nipples until you come" he explains.

"By _you_ do you mean the person who is doing the sucking or the person who gets sucked?" I ask and blush a little.

"I mean you. If I come while getting you off than that's a bonus." He bends down and slowly runs his tongue over my mounds licking them clean. When he's satisfied he starts sucking my right nipple, while kneading my left breast. I arch my back and he switches breasts, sucking on my left nipple now and kneading my right mound. His ministrations are so exquisite that I feel myself approaching the familiar invisible summit. But just as I think that I'm about to come he leaves my now heaving chest and travels down the sweet path he draw with the cake until he reaches my belly button. He dips his tongue inside and a guttural moan escapes my throat. I'm unable to watch him anymore. I lean back into the pillow and close my eyes. I can feel him smile against my skin, but what he's doing next to me distracts me pleasantly. He dips his head between my parted thighs and licks the chocolate frosting off my folds, occasionally slipping his velvet tongue inside, teasing me merciless. When I can't take this anymore I lift myself on my elbows. The sudden change in my position draws his attention and he looks at me with lust filled eyes.

"Please, I can't take this anymore" I say.

"Then I see you have already advanced to lesson number three."

"What's lesson number three?" I ask and he smirks devilishly.

"Shout out my name while you come on my hard cock" he says and I swallow passed the lump in my throat.

He positions himself at my entrance and looks deep into my eyes. I smile at him and he slowly glides inside me. We both moan at the intimate contact and kiss when our bodies start moving as one. I don't know how long I'm going to last, since he worked me up so much today.

He increases his thrusts and I meet each one by raising my hips in anticipation. Our bodies slam together, our breathings erratic, our hearts racing. Sweat beads form on our bodies, already exhausted, but we keep going, racing together as one toward sweet bliss. Tobias leans forward and captures my lips in a passionate kiss that leaves us both breathless and wanting for more. I feel him grow bigger inside me and my own release right around the corner. He looks me deep into the eyes and whispers a sweet I love you which I want to reciprocate, but I'm unable to form anything other the moans or grunts. He increases his speed even more than before pushing me over the edge and I come hard and loud on his rock hard still pistoning cock while he follows me into oblivion.

He collapses over me and I welcome his familiar, warm and loving weight. I wouldn't trade it for the world. I run my hand up and down his back, calming him and even myself after this intense love making session. He lifts himself up on his elbows and looks into my eyes. We smile at each other.

"I love you, Tobias" I finally say while stroking his wet hair back.

"Lesson number four" he says and I give a questioning look. "Four lessons to make you, my sweet love, come. Whenever you are close I whisper that I love you and you come" he says and kisses me again.

"You are a teacher after all, honey. Congratulations" I say.

"Yeah. Impressed?" he asks.

"Not until you solve the integral equation I gave you" I say and he frowns. I start laughing and he soon joins in.

We forget about math and resume his love making lessons, trying to repeat them often enough to make sure we'll never forget them. As if.

 **A/N: For those of you who are curious you can find the equation on Wikipedia by typing in integral equations. It's the first one that appears. The site wouldn't allow me to write the equation correctly.**


	2. AN

**A/N: To all my guest reviewers. Unfortunately I can't reply to you, because you don't have an account on this site. Many of you have requests, especially after reading a one-shot or Tie-in, but I can't communicate with you. If you like you can either create an account on fanfiction dot net or write me your E-Mail address (the site doesn't allow symbols so write just for example yourname at yahoo com, I'll get it) so that I can reply or use my Tumblr (you find the link in my profile).**

 **I would love to answer all your questions, but I can't just add chapters that aren't anything other than author notes.**

 **Best wishes,**

 **Cloakseeker.**


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